Avian influenza infection without animal exposure detected for the first time

The adult patient, who has underlying medical conditions, was admitted to the hospital on Aug. 22, received antiviral medication against the flu, then recovered and was discharged, according to statements from the Centers for Disease Control and Prevention (CDC) and the Department of Health and Human Services from Missouri. Services for seniors.

Because the patient’s type of flu looked suspicious on an initial test, he was sent for additional testing at state and federal labs, which showed it to be H5, also known as bird flu or bird flu.

The CDC said it has not identified any transmission to the patient’s close contacts or anyone else.

Scientists have expressed concern about the increasing number of mammals becoming infected with bird flu, even though human cases remain rare.

They fear that a high rate of transmission could facilitate a mutation of the virus, which could allow it to be passed from one human to another.

Contacted by AFP, the World Health Organization said on Saturday that it was “encouraging that the national disease surveillance system identified this case, that the patient received antiviral treatment and that no further cases were detected among close contacts”.

“It is essential that patient exposure investigations continue, as indicated by national and state authorities, to inform further prevention and response activities,” said Dr Maria Van Kerkhove, WHO Director of Epidemic Preparedness and Prevention and pandemics.

“WHO strongly supports US zoonotic influenza surveillance efforts in the human, environmental and animal sectors,” Van Kerkhove continued.

“It’s important to understand the circulation of bird flu in poultry, wild birds and other animals in the state,” she said of Missouri.

“Stronger animal disease surveillance is essential to protect animal and human health.”

No contact with animals

The person who tested positive for bird flu was the 14th to do so in the US this year and the first without known contact with animals.

Indeed, “no H5 infection has been reported in dairy cattle in Missouri,” the Missouri health department said, although “some cases of H5 have been reported in commercial or backyard herds and in wild birds.”

All previous cases of bird flu in the United States have been among agricultural workers, including the first in 2022.

Bird flu is most commonly found in wild birds and poultry, but has been detected more recently in mammals, with an outbreak in cattle seen across the country this year.

It can occasionally infect humans through close contact or through contaminated environments.

While the CDC continues to rate the risk to the public as low, “circumstances may change rapidly as more information is learned,” it said.

In the decades since H5 was found in humans, there have been rare cases where an animal source cannot be identified.

But so far there has been no evidence of sustained human-to-human transmission, which would significantly increase the level of threat.

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